code: def test_delete_ref_on_object_deletion(ray_start_regular):
      with ray_start_client_server_pair() as pair:
          ray, server = pair
          vals = {
              "ref": ray.put("Hello World"),
              "ref2": ray.put("This value stays"),
          }
  
          del vals["ref"]
  
          wait_for_condition(
              server_object_ref_count(server, 1), timeout=5
          )
  
file_path: ray/python/ray/tests/test_client_references.py
imports: from concurrent.futures import Future
  import pytest
  import ray
  from ray._private.test_utils import object_memory_usage, wait_for_condition
  from ray._raylet import ActorID, ObjectRef
  from ray.util.client import _ClientContext
  from ray.util.client.common import ClientActorRef, ClientObjectRef
  from ray.util.client.ray_client_helpers import ray_start_client_server, ray_start_client_server_pair, ray_start_cluster_client_server_pair
label_desc: Use image node_id 6 for calling a global function with example usage: test_delete_ref_on_object_deletion(ray_start_regular) without return types